If TNT lose the tribunal they face a huge bill for compensating staff for loss of pay.

The Telegraph reported in September last year how more than 200 workers staged a protest by marching through Atherstone town centre before congregating at the front door of the TNT headquarters in Long Street.

Holding banners and chanting “Cut our pay – no way”, the protestors handed over a petition demanding the reinstatement of their bonuses – which for some amounted to £110 a week.

The petition, which contained several hundreds names in support of the outraged workers, was received by security staff. No management representative was available on the day.

Unite union leader Paul Davies said at the time: “The workers are angry and disgusted. They also feel betrayed.

“They are loyal workers who work hard on permanent night shifts and are now having £110 a week docked from their wages.”

Now, around 180 angry workers have instructed Shrewsbury law firm Linder Myers Solicitors to commence an employment tribunal, claiming they felt unfairly treated by the company.

The company has confirmed that six test studies will be heard at the tribunal.

Employment law expert at Linder Myers Solicitors, Alan Lewis, said: “The starting point is to recognise that an employment contract cannot be unilaterally varied by one party without the consent of the other.